Electric coil and core therefor



May 13, 1941. H. E. soMEs ELECTRIC COIL AND CORE THEREFOR Filed April 21, 195e a 2 m 0 j j 9 BY ATTORNEY.

` for instance, of copper.

Patented May 13,k 1941 UNITED STATES PATENT OFFICE 2,241,431 nnlac'rmo con. AND con: miraron Howard E. Somes, Detroit, Mich.

Application apn-11 :1, 193s, sensi N. 203,276 13 claims. (ci. 21a- 13) The invention relates to an electric coil and to a core for such a coil. 'I'he invention is especially applicable for such coils used for heat treating articles by induction heating. 'I'he use of such coils is described in my copending applications:

vSerial No. 50,829, led November 21, 1935: Serial to its assembly with a core of low magnetic reluctance.

Another object is to allow the application'of insulation tothe exposed surfaces of the conductor and between adjacent windings thereof and thereby to form a complete mechanical coil unit which may be assembled with core members being also in the form of pre-assembled units.

The objects of the invention are attained by forming-the core from two parts or units whereby the one unit may at rst be assembled with the coil whereupon the second core unit is brought into place.

Further features, details and advantages of the invention will ibecome clear from the embodiment shown in the attached drawing and from the following description thereof.

The drawing shows a vertical and axial section through an induction heating coil and through a wheel hub to be treated.

In the drawing I designates a tubular member screw threaded at 2 into asecond tubular member` 3 which in turn is connected to the machine as shown in detail in the 'above mentioned applications. c A y Laminations 4 consisting of a metal of low magnetic reluctance are arranged radially around the outer cylindrical surface at the lower end of the tube Ifand are connected to said tube by dovetail connections 5 and C. The upper dove-tail connection comprises a dove-tail carrying ring 1 which is removably connected as by the spring ring 8 lto .the tube I. 'Ihe laminations 4 present by their outer edges a cylindrical surface which is surrounded by a tubular conductor I consisting,

` A't their lower ends' laminations 4 are provided with projections Il extending across the lower end face ofthe conducto: l.

The upper ends of the laminations 4 are free from projections corresponding to the projections I0 at the lower end. Instead thereof a second set of 4radially extending laminations II of a material of low magnetic reluctance is provided which partly overlaps the outer surface at the upper ends of the laminations 4 and which extend radially across the upper end face of the conductor coil l. These laminatlons Il may furthermore have a projection I2 extending into an annular space .between the upper end of the coil I and the inner surface Il of a recessed portion of the hub I4 or the like to be treated. The laminations II are clamped together by dove-tail connectlons I5, I6, partly formed at two annular shaped members I1 and I8 which are drawn together by screw bolts I9. The unit formed by the laminations 4, the members I1 and Il, and the screw bolts I3 is slid over a cylindrical portion of the tube I and removably connected therewith as by a. second spring ring 2l.

The one end 2| of the coil 9 is connected to a tubular member 22 surrounding the tubular members I, I, but separated therefrom by the tubular insulation 2l. The other end of the coil l is connected iby the intermediate pieces 24, 28 and 21 to the tube I. The :tubes l and 22 are connected as shown in the above mentioned earlier applications lto a suitable source of'electric current preferably a high frequency current. The tubular insulation 2l surrounds rthe greater part of the outer surface of the tubular member 22.

The hollow interior of the coiled conductor 9 communicates, by means clearly shown in the drawing, with conduits 29 and 30 respectively which, in turn, are connected to a source of a cooling medium such as water. These conduits 29 and l0 may also serve to make an electrical connection with capacitors (not shown).

A tube II is slidably mounted within the tube I. The lower end of 4the tube SI is centered by a member 32 in the smaller barrel Il of the hub I4 to be treated. Upon removal of the inductor coil and the parts :associated therewith including the tube I out of the hub I4, the lower end of the tube 3| remains within the hub so as to spray a quenching fluid through the apertures I4 thereof. The apertures 34 register with the corresponding apertures Il of the valve member Il which valve member is downwardly moved against the action of spring l1 upon the applicatlonof pressure by the quenching fluid. n

Between th` outside of the laminations 4 and the inner surface of the coil l and between the adjacent windings of the coil I an insulation 3l is inserted and this insulation may also cover the end faces and the outer surface coil. 'I'he connecting extension 2I of the coil is insulated from the laminations 4 and II and from the clamping ring I1 for the laminations I I by a tube or coating 39 of insulating material.

'I'he device shown in the drawing may be assembled in the following manner. The tube I, the laminations 4, the clamping rings 1 and 3, and the connecting pieces 24, 28 and 21 for the lower end of the coil 9, are assembled into one unit. 'I'he laminations II, the clamping rings I1 and I8 and the screw bolts I9 are assembled into a second separate unit. The copper conductor 9 i's formed. into the final shape of the coil whereupon the coil part is coated with frit, the said frit being forced between the conductor to provide for the insulation of adjacent surfaces of said conductor 9 and additional frit may be sprayed on the ends and the outside surface of the coil; when fired, the vitreous enamel so obtained will form an insulating medium to insulate the coils and to combine also the coil into a complete unit mechanically.

After these three units have been made, the vitreous enamel coil is slid into its proper position with respect to the core formed by the laminations 4, whereupon the lower end of the conductor 9 is connected to the piece 24. Now the unit comprising the laminations II is slid into taining parts 32, 36 and 31 inserted.

Obviously, many modifications of the shown embodiment can easily be designed by those skilled in the art and it is the intention to protect each and every modification by the appended claims.

The invention is, for instance, not restricted to the arrangement of the main core member in the interior of the coil, but the expression core is intended also to cover a member of low magnetic reluctance when arranged at the outside of the coil, 'I'he invention is furthermore, for instance, not restricted to any specific form of the coil, which coil instead of being cylindrical may be tapering and an axial section may have any possible conguration in cross section. The invention is also not restricted to induction coils for heat treating by electro-magnetic induction although the invention is especially designated as applicable to such heat treating devices.

What I claim is:

l. A body of low magnetic reluctance having a part of its surface adapted. to telescope unobstructedly from its one end only with a correspondingly shaped electric coil, said body being composed of laminations arranged substantially in the direction of and radially to the axis of the surface part telescoping with said coil; and lamination holding means remote from said surface part and shielded from the coil by the magnetic circuit formed by said body for holding Vsaid laminations together, said holding means being centrally located with respect to the coil.

2. A body according to claim 1. in which each of said laminations has an extension at the one end only extending radially beyond said coil telescoping surface, said extensions being adapted to extend across the one end of said coil.

laniman 3. In combination, a body according to claim 1 with a second body likewise composed of laminations arranged substantially in radial planes to the axis of the coil telescoping surface of said nrst body and provided with means for holding said laminations together shielded from the coil by the magnetic circuit formed by said body; said second body being arranged to extend across the one end of said coil and to form a substantially uninterrupted continuation of said first-named body.

4. In combination with the structure of claim 1, a second body of low magnetic reluctance being composed of laminations arranged in the direction of and extending radially beyond said coil engaging surface of said iirst-namedbody; and lamination holding means shielded from the coil by the magnetic circuit formed by said bodies for holding the laminations of said second body together independently of the other said body.

5. A laminated body of low ,magnetic reluctance having a part of its surface encircling its one axis, substantially free from portions projecting radially beyond any of its portions succeeding in one of the two general directions of said axis, so as to be adapted to permit of an electric coil having a complementary shaped surface part being telescoped with said body in said general direction and holding means for said body shielded from said surface by the magnetic circuit formed .by said body; a second body of low magnetic reluctance having a surface portion complementally shaped to a surface portion of said firstnamed body, said second body -being composed of laminations arranged substantially in the direction of and radially with respect to said axis and being adapted to extend across one end of said coil; and a second lamination holding means shielded from the surface by the magnetic circuit formed by said bodies for holding the laminations of said second body together, one of. said holding means being central with respect to said coil receiving surface. y

6. In a device according to claim 5, the laminations ofsaid second body having extensions adapted to overlie a part of the axially extending surface of the coil opposite the coil surface telescoping with said first named body.

7. In a device according to claim 5, the laminations of said second body having extensions adapted to extend into a space between one axially extending surface portion offsaid coil and a surface portion of a work piece to be treated by said coil.

8. In a devicev according to claim 5, the lami nations of said second body extending in the axial directionof said coil ar substantial distance beyond its coil engaging surface portion, said means for holding said laminations together gripping portions of these extended parts of said laminations. y

K 9. In combination, a member provided with a cylindrical outer surface portion; laminations of low magnetic reluctance extending in the axial direction of and radially from said surface and forming by their outer edges a second cylindrical surface, said laminations being free at one of their ends from parts projecting. radially beyond said second surface; means for rigidly connecting said member and said laminations; an electric conductor surrounding said cylindrical surface; a further member comprising laminations of low magnetic reluctance, these laminations being arranged in the same general axial and radial direction as said first named laminations, said further laminations extending radially outwardly beyond the cylindrical outer surface of said iirst named laminations in the region axially adjacent said electric conductor; and means for rigidly uniting these further laminations shielded from theconductor by the magnetic circuit formed by said laminations, one of said means for rigidly connecting andy means for rigidly uniting the ,laminations being at least partly centrally located with respect to the coil.

10. In a combination according to claim 9, said two members being provided with means for being rigidly but removably connected.

11. In combination an electric coil and a core o1' low magnetic reluctance tting thereinto, said core being composed of laminations extending in.

the axial direction ofsaid coil, said core and said coil having eachone of their axially extending surfaces complementally shaped so as to be slid unobstructedly the one over the other, an additional core member likewise composed of axially extending laminations forming a continuation of saidv tlrstnamed core and extending radially over one of the end faces of said coil and means shielded from the coil by the magnetic circuit for securing said laminations together, a portion of said means being central with respect to the coil.

12. A body oi' low magnetic reluctance having a part of its surface arranged to telescope unobstructedly from its one end with a correspondingly shaped electric conductor coil; a second body of low magnetic reluctance being composed of laminations arranged in the direction of and extending radially beyond said coil engaging surface of said rst named body; and lamination holding means shielded from the coil by the magnetic circuit'l formed by said bodies for holding the laminations of said second body together independently of the other said body, said lamination holding means comprising a projection on each lamination extending in a direction away from the magnetic circuit formed by said bodies and clamping means securing said projections in position.

13. A body of low magnetic reluctance having a part of its surface adapted to telescope unobstructedly from its one end only with a correspondingly shaped electric coil, said body being composed of laminations arranged substantially in the direction of and radially to the axis of the surface part telescoping with said coil; and lamination holding means remote from said surface part and shielded from the coil bythe magnetic circuit formed by said body for holding said laminations together, said lamination holding means comprising a projection on each lamination extending in a direction away from the magnetic circuit formed by said body and clamping means securing said projections in position.

HOWARD E. soMEs. 

